We have never cruised before and have no idea what to expect.
We have been on a few. We first cruised with
DCL in 1999 when our youngest was 5. The only reason we didn't go sooner was because the Magic was late. We were booked to cruise at the end of May in 1998, but the ship wasn't finished on time.
Watching both of our kids grow up on Disney cruises, I would recommend that your daughter go to the age-appropriate club the first evening aboard and meet as many kids her own age as possible. Most of the other kids in the clubs are in the same boat, pun intended, as your daughter. Unless they brought a friend, they don't know anyone either.
I can't speak for your daughter, but by the second day both of our daughters had a group of grils that they were running with.
A few years ago I asked our youngest how she always managed to have an instant group. She told me just what I told you. She would go to the club early the first day before groups had already started to form. She understood that she was not the only one scared because she didn't know anyone, no one knew anyone and everyone was a little scared. She would look for a group of girls that she thought she would enjoy being with to start out. Some trips she had the same group all week, other trips the mix changed over the course of the week, but after every trip she has come home with email addresses, cell phone numbers to text and new people to "friend" on Facebook. The only way to meet others is to go to the age appropriate club.
Don't think we just sent our kids off to their areas and didn't do anything as a family. We required the girls to eat dinner with us every night. Each morning we would look at the navigator and pick out the activities we each wanted to do for the day. Sometimes the club has so much that's appealing it's hard to fit it all in and there were times she didn't want to leave the club when we went to pick her up, but those are good problems to have.
Bill & Laura